Wednesday, August 8, 2012

Scooping the Soviets

Luna 9's view of the lunar surface, the "unauthorized" version [Jodrell Bank Observatory].

Paul D. SpudisThe Once and Future MoonSmithsonian Air & Space

Sir Bernard Lovell, the former Director of Britain’s Jodrell Bank Radio Observatory, died recently at the age of 98. Lovell took the lead in establishing Jodrell Bank near Manchester – one of the world’s premier radio telescopes, a facility that played a lead part in the history of the early space age. One of its most memorable episodes was its role in releasing the world’s first images taken from the surface of the Moon.

In late January 1966, the USSR launched the probe Luna 9 to the Moon. The Soviets had tried to soft-land a spacecraft on the Moon several times previously. Each attempt ended in failure. The United States had the Surveyor project under development, but it had yet to see its first launch. As was their custom, Jodrell Bank tracked the Luna 9 during its coast to the Moon, listening in on its telemetry signals and documenting the position and velocity of the probe throughout its flight. On February 3, 1966, with an encounter speed of 6 meters/second (about 13 mph), the probe “crash-landed” on the lunar surface. Signal transmission from the probe stopped abruptly. The team at Jodrell Bank assumed that the mission was over, surmising that Luna 9 probably hit the Moon too hard or was designed as a crash lander. Then to their astonishment, the probe began transmitting radio signals and the observatory recorded them, uncertain as to their meaning.

Lovell thought – suppose these signals were simply an ordinary telefax communication? If these transmissions were pictures of the lunar surface, perhaps the signals the observatory recorded could be read by a commercial facsimile machine. But Jodrell Bank Observatory had no such machine; the observatory was a scientific laboratory, which in those days displayed its received radio signals in the form of line graphs made by paper strip recorders.

Enter the power of the press! The local office of the London Daily Express rushed a fax machine to the observatory where Lovell and his staff printed out the first picture of another planetary surface ever returned to Earth. Because the staff of the observatory didn’t know anything about Luna 9’s encoding system design, they had to guess at the ratio of the horizontal to vertical dimensions of the image. They guessed wrong. The resulting image showed a jagged, rough peak-like surface, although apparently fine-grained. To both the chagrin and annoyance of the Soviet builders of Luna 9, surface images were released to the world press by the British observatory, leading to an amusing sequence of scientific “instant interpretation” that appeared in the press over the days that followed.

In the early days of lunar science, an intense debate raged over the geologic nature of the Moon. Was it a cold, ancient body that had never undergone melting? Chemist Harold Urey and Astronomer Thomas Gold thought so. They postulated that the Moon was a giant, primitive chondrite meteorite, an unmodified piece of the early solar nebula that would tell us about the cold accretion of the planets. Additionally, Gold was famous for his idea that the dark maria of the Moon were large “dustbowls” in which a heavy spacecraft would slowly sink like a body caught in quicksand on the Earth.

In contrast, many geologists and some astronomers thought otherwise – in their view, the Moon was a body shaped by internal melting, magmatic activity and volcanic eruptions. These “hot moon” people saw evidence for volcanism in many lunar surface features, from the maria to craters. Some, such as the founder of the field of planetary geology, Eugene Shoemaker, had a more nuanced viewpoint, ascribing both impact and volcanic origins to specific features, as appropriate. Although the hard landing American Ranger spacecraft had transmitted high resolution video pictures before hitting the Moon, it did not survive the lunar impact and no one had seen a picture of the surface from a vehicle that landed softly enough to survive and long enough to send back a picture, until now.

A cascade of instant science followed the release of the Jodrell Bank images. Tommy Gold claimed that the pictures validated his dust bowl idea, even though it showed a fine-grained surface strewn with rocks (which Gold thought were clods of fine dust). Gold also said that the Luna 9 capsule was slowly sinking into the surface (in accordance with his model, of course) and would soon sink out of sight. Gerard Kuiper of the University of Arizona thought that the surface of the Moon was composed of bare, dust-free bedrock and so interpreted the new Luna 9 images thusly. U.S. Geological Survey geologist Hal Masursky said that the image looked like the rough, clinkery surface of a jagged lava flow (a surface for which geologists give the Hawaiian name “aa”) and was clearly of volcanic origin. An eager reporter pressed him: this surface is volcanic – isn’t that where gold is sometimes found on Earth? Hal distractedly nodded agreement, leading to the ludicrous headline that Luna 9 had found veins of gold on the Moon.

Alas, there was gold — scientific gold. The distortion of the image caused by a wrong guess of the aspect ratio by the staff of Jodrell Bank soon was corrected when the Soviets released their own version of the image. The lunar surface consists of fine-grained dust, smooth and undulating (because of the presence of a myriad of small surface craters), with the occasional rock lying about — no dust bowls, no bare bedrock, no “quicksand,” no aa lava flows, and no veins of gold. The disappointment of the press was palpable.

The tendency of scientists to see confirmation of their own predispositions in the new data is striking. We all are human, possessing the natural inclination to interpret new data in a way most favorable to our own long-held beliefs. In this instance, a simple and excusable error in the reconstruction of the surface image led to abundant egg on the faces of most of the world’s experts on lunar science. Instant science is often wrong at worst or incomplete at best.